Wheel hub assembly fixture

ABSTRACT

A part clamping fixture assembly for locating and holding a wheel hub assembly for final finishing a flange face of the wheel hub includes a top portion having a bore formed therethrough. The fixture assembly includes a puller member having an upper end for communicating with a drive mechanism and a lower end opposite the upper end. The puller member has an encasing disposed therearound. The encasing has a lower portion for engaging a bearing of the wheel hub assembly and an upper portion in communication with the top portion. The fixture assembly also includes a lift mechanism for lifting the wheel hub assembly generally upward such that a surface of the bearing engages the lower end of the puller member. The lift mechanism is engageable with the lower end of the puller member such that the drive mechanism will rotate the puller member and the lift mechanism together to accomplish the final finishing of the flange face.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present invention claims priority from Applicant's co-pendingApplication Ser. No. 09/414,113, now U.S. Pat. No. 6,485,109, whichclaims priority from Applicant's co-pending provisional application,Serial No. 60/136,535, filed May 28, 1999.

The present invention claims priority from Applicant's co-pendingprovisional application, Serial No. 60/136,535, filed May 28, 1999.

TECHNICAL FIELD

The present invention relates generally to motor vehicle wheel endcomponents. More particularly, the present invention relates to aknuckle/hub assembly having a unique assembly and manufacturing processfor reducing lateral run-out and a unique apparatus for machining therotor-mounting flange surface of the wheel hub.

BACKGROUND ART

Most motor vehicles today include disc brake systems for the front axlewheel assemblies and many further include disc brakes at the rear axleposition. The disc brake rotor is a circular metal disc having opposedbraking surfaces that are clamped by brake pads carried by a brakecaliper to exert a braking effect. The wheel hub typically incorporatesan anti-friction wheel bearing assembly in which one race of the bearingis coupled to the vehicle suspension and the other rotationally mountsthe wheel hub, the brake rotor and wheel. Ordinarily, the rotatingcomponents of the rotor and hub assembly are manufactured separately andassembled together. This enables the brake rotor to be serviced andreplaced if necessary during use. Moreover, the desired materialcharacteristics for a brake rotor and the hub components are different.Although efforts to integrate these components have been proposed, suchan approach has not found widespread acceptance.

In order to enhance performance of the braking system, it is desired tocarefully and accurately control the dimensional characteristics of therotor braking surfaces as the rotor rotates. The thickness variation ofthe disc and the lateral run-out or lateral deflection of the surfacesas they rotate need to be held to minimum tolerances. Similarly, theradial run-out of the outer edges of the braking surfaces need to becontrolled to ensure that the brake pads engage as much of the availablerotor braking surface as possible without overlapping the edges of therotor which gives rise to brake run-out. However, manufacturers havefaced difficulties in achieving enhanced control over these tolerancesdue to the influence of several factors.

Most efforts to date have focused on decreasing run-out by controllingthe dimensional characteristics of the rotor and therefore therelationship of the rotor surface to the wheel hub flange or surface.However, despite the fact that the tolerances and dimensionalcharacteristics of the rotors have improved, performance and run-outproblems still exist. These run-out problems are due in large part toother components of the wheel end assembly, including the bearing/hubassembly, which is comprised of a wheel hub and a bearing or theknuckle/hub assembly, which is comprised of a knuckle, a wheel hub, anda bearing.

One factor that contributes to this run-out is the stack-up of theindividual components in a knuckle/hub assembly, i.e., their combinedtolerances. While the tolerances of each part can be reduced when theyare separately machined, when the parts are assembled, the combinedtolerances stack up, causing run-out that is still relativelysignificant. Another factor that contributes to stack-up is anyvariation in the turning processes that are used to machine the flangesurface, when the wheel hub is individually machined, in an effort tomake it flat with respect to the rotor. Further, the installation andpress condition of the wheel bolts, the assembly process of theknuckle/hub assembly, and improperly pre-loaded bearings, can all causemisalignment of the hub surface with respect to the rotor and thus causeunacceptable run-out. This run-out can cause premature failure of thebrake lining due to uneven wear which requires premature replacement ofthe brake lining at an increased expense. Further, problems due torun-out include, brake judder, steering wheel “nibble” and pedal pulsesfelt by the user, and warped rotors which result in brake noise anduneven stopping.

Presently available manufacturing methods and designs of knuckle hubassemblies limit the accuracy to which lateral run-out of brakingsurfaces can be controlled. These methods and designs are alsoinsufficient to solve the problems associated with run-out, as discussedabove. Current methods typically involve finishing the knuckle and thehub individually and then assembling the machined parts to form acompleted knuckle/hub assembly. These methods, however, do not solve therun-out problems due to the factors discussed above, including stack-uptolerances, turning process variations, and wheel bolt and bearinginstallations.

Other options have been considered in an effort to solve the run-outproblem, but they also all suffer from a variety of disadvantages. Onecontemplated option for reducing run-out is to separately decrease therun-out of each individual component, by decreasing their respectivetolerances during manufacture and then assembling the components. The“stack up” of tolerance variations related to such an approach is stillsignificant and provides only limited system improvement at an increasedmanufacturing cost. Another contemplated option includes tightening thepress-fit tolerance variation between the knuckle, the wheel hub, andthe bearing. This, however, significantly increases the difficulty inthe assembly process as well as increases the manufacturing cost.Further, this option does not provide the desired reduction in systemrun-out.

It would therefore be advantageous to design a knuckle/hub assembly fora motor vehicle that decreases system run-out without significantlyincreasing the manufacturing cost of the assembly or increasing themanufacturing difficulty.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide aknuckle/hub assembly and a method for manufacturing same that providesreduced wheel hub lateral run-out.

It is a further object of the present invention to provide a knuckle/hubassembly and a method for manufacturing same that results in a brakeconfiguration which minimizes brake noise and uneven stopping.

It is still a further object of the present invention to provide aknuckle/hub assembly and method for manufacturing same that results in abrake configuration which minimizes uneven brake lining wear and thusthe need for frequent lining replacements.

It is a related object of the present invention to provide a knuckle/hubassembly and a method for manufacturing same that results in a brakeconfiguration which increases the life of vehicle brake linings.

It is yet another object of the present invention to provide aknuckle/hub assembly and a method for manufacturing same that results ina brake configuration which provides improved performance at relativelylower cost.

It is yet a further object of the present invention to provide a tool toallow for the machining of a knuckle/hub assembly to provide decreasedlateral run-out on the outboard wheel hub flange face.

In accordance with the objects of the present invention a knuckle/hubassembly for a motor vehicle is provided. The knuckle/hub assemblyincludes a knuckle having a plurality of apertures formed therein forattachment of the knuckle to a vehicle. The knuckle also includes abearing retention portion. The knuckle bearing retention portion is incommunication with a bearing through press-fitting. The bearing in turnis in rotational communication with a wheel hub. The wheel hub includesa neck portion that is pressed into the bearing, and a flange. Theflange has a flange face, which includes an outer portion, an innerportion, and a relief channel that is formed in the flange face betweenthe outer portion and the inner portion. The relief channel has aplurality of bolt holes formed therein with each of the plurality ofbolt holes receiving a wheel bolt passed therethrough. The inner portionand the outer portion are disposed on the same plane and are parallel tothe caliper mounting features, and wherein the inner and outer portionshave minimal run out with respect to the bearing axis of rotation.

In accordance with another object of the present invention, a method forforming a knuckle/hub assembly having reduced run-out is provided. Themethod includes providing a knuckle having a generally circular boreformed therein. The generally circular knuckle bore has a bearingpress-fit therein. A wheel hub having a neck portion and a flangeportion with a flange face is provided. The flange face is then machinedto form a relief channel therein, which divides the flange surface intoan inner portion and an outer portion. The inner portion and the outerportion of the wheel hub flange face are each finished. The reliefchannel has a plurality of wheel bolts press-fit into bolt holes formedtherein. The neck portion of the wheel hub is then journaled into thebearing such that the wheel hub can rotate with respect to the knuckle.The knuckle/hub assembly is then mounted such that the flange face isthen final finished with the inner portion and the outer portion beingco-planar and parallel with respect to the caliper ears.

In accordance with another object of the present invention, an assemblyfor holding a knuckle/hub assembly while it is final finished isprovided. The assembly includes a standard lathe machine with a fixturefor clamping and locating the knuckle/hub assembly. The fixture appliesa clamping force to the wheel hub and the inner race of the bearing togenerate a pre-load on the bearing. The fixture also holds the knucklein place so that the wheel hub may be rotated. Thereafter, the inner andouter surfaces of the flange face are final finished so that they areflat and co-planar with respect to each other. These two surfaces haveminimal run-out when measured back to the knuckle/hub assembly's axis ofrotation.

These and other features and advantages of the present invention willbecome apparent from the following description of the invention whenviewed in accordance with the accompanying drawings and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a knuckle/hub assembly in accordancewith a preferred embodiment of the present invention;

FIG. 2 is an exploded cross-sectional view illustrating the componentsof a knuckle/hub assembly and a brake rotor in accordance with apreferred embodiment of the present invention;

FIG. 3 is a cross-sectional view of the knuckle/hub assembly inaccordance with a preferred embodiment of the present invention;

FIG. 4 is a rear view of a knuckle/hub assembly in accordance with apreferred embodiment of the present invention;

FIG. 5 is an end view of a wheel hub flange face in accordance with apreferred embodiment of the present invention;

FIG. 6 is a cross-sectional view of the wheel hub of FIG. 5 along theline 6—6;

FIG. 7 is a top view of a manufacturing fixture assembly for use in thegeneration of a knuckle/hub assembly in accordance with a preferredembodiment of the present invention;

FIG. 8 is a bottom view of a manufacturing fixture assembly with aknuckle/hub assembly clamped therein in the direction of the arrow 8 inFIG. 9 in accordance with a preferred embodiment of the presentinvention;

FIG. 9 is a cross-sectional view of the manufacturing fixture assemblyand knuckle/hub assembly clamped therein of FIG. 7 in the direction ofthe arrows 9—9;

FIG. 10 is a cross-sectional view of a puller member of themanufacturing fixture assembly of FIG. 7 in the direction of the arrows10—10;

FIG. 11 is a cross-sectional view of the manufacturing fixture assembly,with a knuckle/hub assembly positioned therein, of FIG. 9 in thedirection of the arrows 11-11;

FIG. 12 is a cross-sectional view of the manufacturing fixture assembly,with a knuckle/hub assembly positioned therein, of FIG. 9 in thedirection of the arrows 12—12;

FIG. 13 is a cross-sectional view of an alternative embodiment of awheel hub assembly in accordance with the present invention; and

FIG. 14 is a cross-sectional view of another alternative embodiment of awheel hub assembly in accordance with the present invention.

BEST MODE(S) OF THE INVENTION

FIGS. 1 through 4 illustrate a preferred knuckle/hub assembly, asgenerally indicated by reference number 10, in accordance with thepresent invention. The assembly 10 is comprised of a variety ofcomponents, including a knuckle 12 and a wheel hub 14. The knuckle 12 ispreferably constructed of metal and is generally formed by casting whilethe wheel hub 14 is preferably constructed of metal. The knuckle and hubcan obviously be formed of other materials. The knuckle 12 preferablyhas a generally circular bore 16 formed therein and a plurality ofoutwardly extending appendages 18 that attach to the vehicle through aplurality of apertures 20 formed in the plurality of legs 18, as is wellknown in the art.

The bore 16 has a recess 22 formed therein bounded by an upper snap ringgroove 24 and a lower snap ring 26 or shoulder for receiving a bearing28 press fit therein. A snap ring 29 is preferably press fit orotherwise secured into the upper snap ring groove 24 prior to engagementof the bearing 28 with the knuckle 12. It should be understood thatwhile the illustrated assembly has a bore 16 formed in the knuckle 12,the bearing 28 can be attached or secured to the knuckle 12 in a varietyof configurations. For example, the bearing 28 can be mounted to anupper surface or other portion of the knuckle 12. Alternatively, thebearing 28 can be only partially disposed in the bore 16. Additionally,the bore 18 can be eliminated altogether.

The bearing 28 preferably has an outer race 31 and an inner race 33.However, it should be understood that a variety of different bearingsmay be utilized as well as a variety of different knuckle/bearingattachment configurations. For example, instead of being press-fit witha snap ring, i.e., between the upper retention ring 24 and the lowerretention ring 26, the bearing 28 may be press-fit without a snap ringand held in place with a nut or other known securing methods.Alternatively, the outer race 31 may be integrally formed with theknuckle 12 (FIG. 14) or may be configured as an orbital formed outerrace rotation bearing/knuckle assembly. Further, the bearing outer race31 could alternatively be bolted to the knuckle 12 such that the innerrace 33 rotates with the wheel hub 14. Moreover, the inner race 33 maybe integrally formed with the wheel hub 14 (FIG. 13). Further, a spindleconfiguration having a non-driven outer race rotation may also beutilized.

In the preferred embodiment, the wheel hub 14 has a neck portion 30 anda flange portion 32. The neck portion 30 is preferably pressed intocontact with the inner race 33 of the bearing 28 so that the wheel hub14 can rotate with respect to the knuckle 12, as shown in FIG. 3.Alternatively, the neck portion 30 may be integrally formed with theinner race 33 or the outer race 31. It should be understood that otherwheel hub/bearing configurations may also be utilized.

The flange portion 32 has a flange face 34 and a wheel and rotor pilotportion 36. The wheel and rotor pilot portions 36 extend generallyupwardly from the flange face 34 and has an inner surface 38, whichdefines a spline 40. The wheel hub 14 also has a plurality of bolt holes42 formed in the flange face 34 through which a plurality of respectivewheel bolts 44 are passed. The plurality of wheel bolts 44 are attachedto the flange face 34 in a predetermined pattern and on the same pitchcircle diameter. The wheel bolts 44 are oriented with the threaded endsextending outwardly so as to connect a rotor 46 and associated wheelonto the hub 14 in a fashion, which is more clearly described below.Alternatively, the wheel hub 14 may have bolt holes 42 that receive lugnuts that are attached to a vehicle wheel and are passed through thebole holes 42 when the wheel is attached to the wheel hub 14.

As best shown in FIG. 2, the rotor 46 comprises a cup 48 with a centralaperture 50 adapted to receive therethrough a wheel shaft (not shown)affixed to the wheel and rotor pilot portions 36 and extending outwardlyfrom the flange face 34. The cup 48 is dimensioned to receive the hubflange portion 32 and includes at its outer end an annular flange 52having a plurality of apertures 54 lying in the same pitch circlediameter relative to the wheel shaft as the wheel bolts 44 and having asimilar pattern so as to accommodate the wheel bolts 44 therethrough.

A pair of parallel, annular discs 56 spaced from each other by aplurality of rectangular fillets 58 extend outwardly from the cup 48 anddefine braking surfaces for a plurality of brake calipers (not shown).The completion of the assembly to the wheel is done by positioning thewheel over the bolts 44 and the threading nuts (not shown) over thebolts 44 so as to secure the wheel between the nuts and the rotor 46.This invention addresses, among other things, the problems, which occurbetween the mating surfaces of the hub flange portion 32 and the rotor46.

Turning now to FIGS. 5 and 6, which illustrate the preferred wheel hub14 and flange portion 32 of the present invention. The flange face 34has a relief channel 60 machined therein. It should be understood thatthe relief channel 60 may also be forged into the flange face 34 or maybe formed by other known methods. The relief channel 60 divides theflange face 34 into an outer flange surface 62 and an inner flangesurface 64. The relief channel 60 is turned into the flange face 34 sothat the plurality of bolt holes 42 lie in the relief channel 60. Theplurality of bolt holes 42 may be formed either before or after therelief channel 60 has been formed. The relief channel is preferably setbelow the level of the flange face 34, this is to eliminate any surfaceunevenness caused by press-fitting the wheel bolts 44 into the boltholes 42. Any unevenness due to press-fitting of the wheel bolts 44 iscompensated for by the relief channel 60 as any unevenness will not beraised with respect to the flange 62, 64, and therefore does notcontribute to any run-out. The relief channel 60 also allows for finalfinishing or finish turning to be performed on the assembly 10 after thebolts 44 have been seemed to the wheel hub 14.

The relief channel 60 is preferably formed in the flange surface 34prior to the knuckle 12, the bearing 28, and the wheel hub 14 beingassembled. However, it should be understood that the relief channel 60can be formed in the flange surface 34 after the wheel hub 14 isassembled to the bearing 28 and the knuckle 12 and before the wheelstuds 44 are press-fit therein. In accordance with the preferred methodof forming, the wheel hub 14 has the relief channel 60 formed therein.Thereafter, the outer flange surface 62 and the inner flange surface 64are finished. After the finishing process has been completed, the wheelbolts 44 are press fit into the bolt holes 42. Thereafter, the hub 14 ismounted to the bearing 28 and the knuckle 12 to form the completedknuckle/hub assembly 10.

The assembly 10 is then placed into a clamping apparatus, as isdiscussed in more detail below, where it is finish turned or finalfinished to provide a flat outer flange surface 62 and a flat innerflange surface 64 that will contact the rotor 46 and thus, minimize anyrun out. The refinishing will provide an inner flange surface 64 and anouter flange surface 62 that are co-planar with respect to each other soas to provide a flat flange surface 34. The re-finishing processminimizes run-out with respect to not only the rotor, but also to thecenter of rotation of the assembly 68, as established by the bearing 28.Further, the method and configuration of the present invention allowsthe distance between the caliper ears and the flange surfaces 62, 64 tobe accurately controlled. Additionally, the parallelism between thecaliper ears and the flange surfaces 62, 64 can also be accuratelycontrolled. In the preferred embodiment, each flange surface has aflatness of 20 μm or better. Additionally, the run-out is minimized to14 μm or better and the co-planarness of the inner and outer surfaces62, 64 is 20 μm or better. However, the flatness requirements may bevaried.

FIGS. 7 through 12 illustrate a preferred part clamping fixture 70 inaccordance with the present invention. The part clamping fixture 70 ispreferably incorporated into a lathe machine (not shown) and is used tolocate and hold the knuckle/hub assembly 10 for refinishing, inaccordance with the process described above.

As shown in FIG. 7, the part clamping fixture 70 includes a generallyflat top surface 72 for abutting a portion or surface of the lathemachine. The generally flat top surface 72 includes an opening 74 formedtherein in which a split collar 76 is generally positioned forengagement with a drive motor from the lathe. The split collar 76 isdisposed such that it is rotatable with respect to the opening 74. Thesplit collar 76 has a top surface 78 with a plurality of drive motorengagement notches 80 that communicate with the drive motor from thelathe in order to rotate the split collar 76.

With reference to FIGS. 7 through 12, the part clamping fixture 70 isshown in more detail. The fixture 70 includes a plurality of keys 82that fit into recesses 84 formed in the generally flat top surface 72.The keys 82 have fasteners 86 that pass through both the keys 82 and thegenerally flat top surface 72 to secure the keys 82 to a spacer plate88. The spacer plate 88 is disposed on top of a base plate 90 with thetwo plates 88, 90 being secured by standard fasteners 92 that extendthrough the generally flat top surface 72.

The split collar 76 has a bore 94 formed therein in which a toothed gear96 is disposed. The toothed gear 96 is secured to a puller member 98that, when lowered by the lathe, extends generally downward and intocommunication with the knuckle 12. The toothed gear 96 is rotatable withrespect to the split collar 76 and is supported at a bottom surface 100by a u-joint adapter 102 that has a central opening 104 formed thereinthat encompasses the puller member 98.

The part clamping fixture 70 has a right housing portion 106, a rightcover portion 108, and a right pull piston 110 disposed in the righthousing portion 106. The part clamping fixture 70 also includes a lefthousing portion 114, a left cover 116, and a left pull piston 118disposed within the left housing portion 114. Both the right pull piston110 and the left pull piston 118 are secured to the base plate 90 byrespective fasteners 112, 120. Each of the right housing portion 106 andthe left housing portion 114 are moveable with respect to the respectivepull pistons 110, 118 such that respective chambers 122, 124 are formedbetween each housing portion 106, 114. Each chamber 122, 124 has anorifice 126, 128 in fluid communication therewith allowing fluid toenter and exit the respective chamber 122, 124 to assist in moving theright and left housing portions 106, 114 upwardly and downwardly. Theleft and right chambers 122, 124 are sealed from their respectivehousings 106, 114 by a plurality of o-rings 130. Obviously any othersealing mechanism may alternatively be utilized. The left pull piston118 is preferably smaller in length and diameter than the right pullpiston 110 to ensure that equal forces are applied to the knuckle 12. Itshould be understood that the size of the pull pistons 110 and 118 mayvary depending upon the knuckle configuration.

As shown in FIG. 9, a bayonet 132 is preferably inserted into the spline40 defined by the inner surface 38 of the wheel pilot portion 36 of theflange portion 32. The bayonet 132 is for engagement with the pullermember 98 to lift the knuckle/hub assembly 10, as described in moredetail below. The bayonet 132 preferably engages a washer bore or face133 in order to lift the assembly 10.

As shown in FIG. 11, the right housing portion 106 is retained inproximity with the base plate 90 by a pair of retaining blocks 134. Eachof the retaining blocks 134 has a supporting portion 136 that engages aflange portion 138 of the right housing portion 106. Each of theretaining blocks 134 is secured to the base plate 90 by a fastener 140or the like. A pair of guide pins 142 are disposed in the right housingportion 106. Each of the guide pins 142 is secured to the base plate 90at an upper end 144 and each is in communication with a spring 146 at alower end 148. Each spring 146 fits within a recess 150 formed in thelower end 144 of each of the guide pins 142 and extends downwardly intocontact with the right housing portion 106. The biasing force from thesprings 146 helps bias the right housing portion 106 away from the guidepins 142.

As also shown in FIG. 11, the right housing portion 106 includes a pairof bores 152 within which a respective piston 154 reciprocates. Eachpiston 154 moves between a normally unengaged position and a knuckleengaging position. The bores 152 are each sealed adjacent the outer ends156 of the pistons 154 by an end cap 158. The inner ends 160 of each ofthe pistons 154 has a gripper portion 162 and a swiveling gripperportion 164 which allow the piston 154 to engage and hold the upperstrut arm 155 of the knuckle 12 when the piston 154 is in the knuckleengaging position. Each piston 154 reciprocates within a bushing 166secured within the respective bore 152 to ensure proper alignment of thegripper portions 162 and the swiveling gripper portions 164 with respectto the upper strut arm 155.

Turning now to FIG. 12, which is a cross-sectional view of the fixtureassembly 70 through the left housing portion 114. The left housingportion 114 is also retained in proximity with the base plate 90 by apair of retaining blocks 168. Each of the retaining blocks 168 has asupporting portion 170 that engages a flange portion 171 of the lefthousing portion 114. Each of the retaining blocks 168 is secured to thebase plate 90 by a fastener 172 or other securing means. A pair of guidepins 174 are disposed in the left housing portion 114. Each of the guidepins 174 is secured to the base plate 90 at an upper end 176 and each isin communication with a spring 178 at a lower end 180 of the guide pins174. Each spring 178 fits within a recess 182 formed in the lower end180 and extends downwardly into contact with the left housing portion114. The biasing force from the springs 178 helps bias the left housingportion 114 away from the guide pins 174. The left guide pins 174 arepreferably smaller in length and diameter than the right guide pins 142.

As also shown in FIG. 12, the left housing portion 114 includes a pairof bores 184 within which a respective piston 186 reciprocates. Eachpiston 186 moves between a normally unengaged position and a knuckleengaging position. The bores 184 are each sealed adjacent the outer ends188 of the pistons 186 by a respective end cap 190. The inner ends 192of each of the pistons 186 have a gripper portion 194 and a swivelinggripper portion 196 which allow the pistons 186 to engage and clamp thelower ball joint 198 of the knuckle 12 when the pistons 186 are in aknuckle engaging position. Each piston 186 reciprocates within a busing188 secured within each bore 184 to ensure proper alignment of thegripper portion 194 and the swiveling gripper portion 196 with respectto the lower ball joint 198.

Referring now to FIGS. 9 and 10, which illustrate the puller member 98and the surrounding encasing 200. The puller member 98 has a headportion 202 around which the toothed gear 96 is located, a neck portion204 which passes through the opening 104 in the u-joint adapter 102, anda stem portion 206 which is rotatable within a bore 208 formed in thesurrounding encasing 200. The surrounding encasing 200 has a pluralityof bearings 210 disposed around the bore 208 to assist in the rotationof the stem portion 206.

The encasing 200 includes an upper body portion 212 that has an upperend cap portion 214 disposed thereabove, a lower end cap portion 216disposed therebelow, and a spacer portion 218 disposed between the upperbody portion 212 and the lower end cap portion 216. The components ofthe upper body portion 212 are held together by a fastener 220 or othersecuring mechanism. The encasing 200 also includes a lower stop portion222 which is secured to an upper end cap 224 by a fastener 226 or othersecuring mechanism. The upper body portion 212 and the lower stopportion 222 are surrounded by a body portion 228 having a stop portion230 secured thereto. The encasing 200 is preferably secured to theunderside of the base plate 90 by a plurality of fasteners 232, such asbolts or other securing mechanisms.

An upper reservoir 234 is preferably formed in the upper body portion212. The upper reservoir 234 is in fluid communication with a fluidinlet port 236 for receiving hydraulic fluid therein. The upperreservoir 234 is also in fluid communication with a first fluid orifice238 formed in the stem portion 206 of the puller member 98. The firstfluid orifice 238 is in fluid communication with an internal fluidpassageway 240 which is in fluid communication with a second fluidorifice 242 formed in the stem portion 206. Fluid that passes throughthe second fluid orifice 242 is passed into a lower reservoir 244. Thelower reservoir 244 is formed between the lower stop portion 222 and theupper end cap 224.

The stem portion 206 has an annular flange 246 integrally formedthereon. The annular flange 246 is preferably disposed in the lowerreservoir 244. The annular flange 246 and the upper end cap 224 are inmechanical communication through the inclusion of a plurality of springs248 disposed in recesses 250, 252 formed in their respective surfacesand a spring drive pin 254. Thus, as hydraulic fluid enters the lowerreservoir 244 through the second fluid orifice 242, the annular flange246 is caused to move upward against the force of the springs 248.

In operation, a knuckle/hub assembly 10 which is to be refinished inaccordance with the process, as described in detail above, is located inthe lathe and generally beneath the part darning fixture 70. Theknuckle/hub assembly 10 is preferably resting on a pallet or otherstructure with unobstructed passages. After the knuckle/hub assembly 10has been located on the pallet beneath the part clamping fixture 70, thebayonet 132 enters the spline 40 of the assembly 10 by passing upthrough the pallet upon which the assembly 10 is resting. The bayonet132 is pressed upward until a shoulder portion 256 contacts the washerface 133 of the flange portion 32 forcing it upward. The assembly 10 islifted by the bayonet 132 at least enough so that the wheel studs 44 areclear from the pallet.

Thereafter, the lathe lowers the puller member 98 and the pullerencasing 200 through the opening 74 and into communication with theknuckle 12. The stem portion 206 of the puller member 98 has a recess258 formed at its lower end 260 which is opposite the head portion 202.The recess 258 is non-uniform in diameter as in one orientation, it islarge enough to receive a rounded top portion 260 of the bayonet 132therewithin. However, when the stem portion 206 is rotated 90 degrees,its diameter is not large enough to receive the rounded top portion 260therewithin or to allow the rounded top portion 260 to be withdrawn fromthe recess 258 if it is positioned therein. Thus, when the puller member98 is lowered, it is oriented so as to receive the rounded top portion260 therewithin.

After the puller member 98 and the puller encasing 200 have beenlowered, the pair of right pistons 156 and the pair of left pistons 186are hydraulically actuated in order to apply a pinching or clampingforce to the knuckle 12. The right pistons 156 apply a clamping force tothe opposing sides of the upper strut arm 155 through the use of thegripper portions 162 and the swiveling gripper portions 164. Similarly,the left pistons 186 apply a clamping force to the opposing sides of thelower ball joint 198 through the use of the gripper portions 194 and theswiveling gripper portions 196. The lifting of the assembly 10 by thebayonet 132 and the lowering of the puller member 98 forces the knuckle12 into contact with the stop portion 230. The stop portion 230 has anannular shoulder 262 which engages knuckle 12. These actions locate theknuckle/hub assembly 10 within the lathe and also fix the knuckle 12 tothe lathe separately from any drive mechanism. Further, the knuckle 12acted on by the pullers and grippers so that the knuckle is fixed andlocated. The knuckle 12 is not exposed to any bearing pre-load force.

After the assembly 10 is located, the bayonet 132 is engaged by rotatingthe puller member 98 and the puller encasing 200 with respect to thesurrounding body portion 228, the puller member 98 and the pullerencasing 200 are free to rotate with respect to the body portion 228 andare rotated 90° in order to engage the bayonet 132. Thereafter, aclamping force is introduced by applying pressure to the annular flange36 by introducing hydraulic fluid into the lower reservoir 244 throughthe second fluid orifice 242 forcing the puller 20 upward. By pullingthe puller member 98 up, the bayonet 132 is also pulled upward such thatthe lower stop portion 222 sits on the inner race 31 of the bearing inorder to apply a force thereto and thus preload the bearing 28.

After the assembly 10 has been located and clamped as described above,the final finishing process of the inner and outer surfaces 62, 64 ofthe hub flange face 34 can be performed by a finishing tool. In such aprocess, the hub 14 is driven such that it is rotating with respect tothe knuckle 12 in which is fixed. The finishing tool is also preferablysingle tool such as a CNC tool, as is well known in the art. However, avariety of the other finishing tools may alternatively be utilized.

One of the features of the fixture assembly 70 is to turn the wheel hub14 and the bearing 28 compliantly, such that the stem portion 206 andthe annular flange 246 are free to float and follow the knuckle/hubbearing's axis of rotation. It is further preferred that the flangesurface 34 is probed before final finishing to ensure a small finalfinish cut, i.e., decreasing the amount of material removal that isrequired during the final finish cut. This helps control the distancebetween the caliper ears and the flange face 34.

Other objects and features of the present invention will become apparentwhen reviewed in light of detailed description of the preferredembodiment when taken in conjunction with the attached drawings andappended claims.

What is claimed is:
 1. A part clamping fixture assembly for locating andholding a wheel hub assembly for final finishing of a flange face of thewheel hub, comprising: a top portion having a bore formed therethrough;a puller member having an upper end for communicating with a drivemechanism and a lower end opposite said upper end; an encasing which isdisposed around said puller member, said encasing having a lower portionfor engaging a bearing of the wheel hub assembly and an upper portion incommunication with said top portion, wherein said lower portion of saidencasing is moveable with respect to said puller member in order tobring a bottom surface of said lower portion into engagement with saidbearing to apply a preload thereto; and a lift mechanism for lifting thewheel hub assembly generally upward such that a surface of said bearingengages said lower end of said encasing, said lift mechanism beingengageable with said lower end of said puller member such that saiddrive mechanism will rotate said puller member and said lift mechanismtogether to accomplish the final finishing of the flange face.
 2. Theassembly of claim 1, wherein said lift mechanism comprises a bayonetwhich is inserted into a bore formed in the assembly.
 3. The assembly ofclaim 2, wherein said bayonet includes a head portion having a diameterwhich is larger than the diameter of said bore in order to effectuatelifting of the assembly.
 4. The assembly of claim 3, wherein saidbayonet includes a stem portion that is matingly receivable within arecess formed in said lower end of said puller member to assist inapplying a preload to said bearing during the final finishing process.5. The assembly of claim 1, wherein said movement of said lower portionof said encasing is hydraulically controlled.
 6. A fixture assembly forlocating and holding a wheel hub assembly for final finishing of aflange face of the wheel hub, comprising: a puller member having anouter housing, said outer housing intended to engage a bearing of thewheel hub assembly to apply a force thereto, said outer housing beingmoveable with respect to said puller member in order to bring a bottomsurface of said outer housing into engagement with said bearing to applya preload thereto; a drive mechanism for causing a wheel hub of thewheel hub assembly to rotate with respect to said bearing; and a liftmechanism for lifting the wheel hub assembly upward such that a surfaceof said bearing contacts said outer housing, said lift mechanism beingengageable with said puller member such that said drive mechanism willrotate said puller member and said lift mechanism together to accomplishthe final finishing of the flange face.
 7. The assembly of claim 6,wherein said lift mechanism includes a bayonet which is inserted into abore formed in the assembly.
 8. The assembly of claim 7, wherein saidbayonet has a head portion with a diameter that is larger than adiameter of said bore in order to effectuate lifting of the assembly. 9.The assembly of claim 8, wherein said bayonet has a neck portion thatextends from said head portion and through said assembly bore.
 10. Afixture assembly for receiving a wheel hub assembly having a wheel hubflange face, a wheel hub neck portion, and a bearing, the assemblycomprising: a rotating member that is intended to be received withinsaid wheel hub neck portion, said rotating member being inserted intosaid neck portion from a rear side adjacent said bearing; a housingportion disposed about and moveable with respect to said rotating memberin order to bring a bottom surface of said housing portion intoengagement with said bearing to secure it while allowing rotation ofsaid wheel hub; a drive mechanism that is in communication with saidrotating member causing it to rotate with respect to said housingportion; and a hub assembly movement mechanism being engageable withsaid bearing to allow the wheel hub assembly to be moved such that saidbearing engages said housing portion, said hub assembly movementmechanism being releasably engageable with said rotating member suchthat said drive mechanism will cause said rotating member and said hubassembly movement mechanism to rotate together thereby turning saidwheel hub to allow final finishing of said wheel hub flange face. 11.The assembly of claim 10, wherein said hub assembly movement mechanismlifts the hub assembly.
 12. The assembly of claim 10, wherein said hubassembly movement mechanism consists of a bayonet.
 13. The assembly ofclaim 12, wherein said bayonet includes a head portion that is largerthan the diameter of said neck portion in order to effectuate thelifting of the assembly.
 14. The assembly of claim 10, wherein thefixture assembly is incorporated into a lathe machine.